In the present study, the application of Pongamia natural ester as a renewable green dielectric (GD) applied in the electric discharge machining (EDM) of AISI 2507 super duplex steel. This investigation aims to study the effect of Pongamia green dielectric in the EDM process. The major process variables such as pulse-on time (TON), pulse-off time (TOFF), peak current (IP), voltage (v) and inter-electrode gap (IEG) on performance measures like material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR). The Taguchi's orthogonal array (OA) L27 has been selected for this experimentation. The choice of optimal input parameter settings that are attained by multi-response optimisation of performance measures using Taguchi-fuzzy-TOPSIS technique is TON = 500 µs, TOFF = 30 µs, IP = 15 A, v = 40 V and IEG = 180 µm. The optimal settings have increased the productivity aspects by the four decision makers (DM) order priorities. The optimised results, shown the improvement in MRR with the minimised EWR and SR. The optimal settings of the process for improved machining responses were identified by Taguchi's response graph and analysis of variance (ANOVA). The recast layer and micrographs were examined utilising scanning electron microscopy (SEM). Copyright © 2020 Inderscience Enterprises Ltd.